


The Temptation of Bellatrix Black

by dexstarr



Category: Harry Potter - J. K. Rowling
Genre: Blackcest, Community: hp_yule_balls, Cunnilingus, F/F, Femslash, Girls Kissing, Hogwarts Prefects' Bathroom, Light Bondage, Orgasm Delay/Denial, Watersports
Language: English
Status: Completed
Published: 2017-08-31
Updated: 2017-08-31
Packaged: 2018-12-22 00:16:04
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,798
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11955711
Author URL: https://archiveofourown.org/users/dexstarr/pseuds/dexstarr
Summary: Bellatrix has been looking forward to this for months, and so has Narcissa.





	The Temptation of Bellatrix Black

**Author's Note:**

> Harry Potter is not mine and no profit is made from this work. Written for the LJ community [hp_yule_balls](https://hp-yule-balls.livejournal.com). Event: 2010 Exchange Fest.

An uncharacteristic smile tugged at her lips when she spotted a familiar blonde head across the hall — no one else at Hogwarts had Narcissa's precise shade of pale gold hair. Usually Bellatrix Black sneered at everyone, professors included, but a glimpse of her little sister always brightened her day. Especially when she thought about what Cissy wore under her school uniform.   
  
Wait. Cissy — she wasn't wearing  _trousers_ , was she? Bella's brow furrowed when she confirmed that yes, her sister was indeed wearing trousers instead of a skirt. "Narcissa!" she called, her voice sharp, her eyes narrowed in anger. "Come here." She stepped back into an alcove in the hall and waited for Narcissa to wade through the crowds of people.  
  
"Explain," Bellatrix snapped when her sister reached her. "Those," she indicated the trousers Narcissa wore, "are not what I like you in."   
  
"It's freezing today, Bella! You know how I hate being cold," Narcissa said petulantly, and Bella nodded in agreement, her expression softening. She knew Cissy had an almost abnormal sensitivity to cold. "It's not like they're mine, anyway. I nicked them from Andromeda's dresser."   
  
Bella could see that was true — the grey trousers were too big for her sister's slim frame, almost absurdly so. Narcissa must have been very cold indeed to risk looking so silly. "That doesn't make it any better, Cissy," she said firmly, smothering a laugh. "You're a witch, you could have cast a warming charm." Narcissa's cornflower blue eyes widened — clearly she hadn't thought of doing that. "Do you need a reminder of what I like, dear sister?"  
  
Narcissa's fear dissipated at Bella's teasing tone; she knew her sister was toying with her, and this was a game they both enjoyed. "No, Bella. I won't do it again," she said cheekily.  
  
"No, you won't. Meet me in the prefects' bathroom during dinner." Bellatrix smirked when Narcissa looked up at her with big blue puppy eyes, asking for an explanation, but said, "Off to class now," and pushed her sister back into the hallway.  
  


*     *     *

  
  
Cissy wasn't waiting when Bellatrix entered the prefects' bathroom, which furthered her resolve to do something …  _special_  to show her sister the error of her ways. She loved Narcissa's adorable impertinence, but she also liked obedience.   
  
Pulling her wand from a pocket in her robes, she transfigured one of the benches dotting the room into a chaise lounge, complete with several cushions. Bella draped herself over the transformed chair, examining her nails as she waited impatiently for her sister. The minutes ticked by slowly, first one, then five, then ten, before the door opened.   
  
Narcissa rushed into the room and skidded to a halt when she saw that Bellatrix was already there. "I'm sorry — Professor Slughorn — I couldn't get away," she panted, pressing a hand against the stitch in her side.   
  
Bella didn't look up from her nails until Narcissa's breathing slowed, and then she said, "Clothes off." While Narcissa obeyed, stripping off her robes, jumper, shirt, tie, trousers, and shoes, Bella pointed her wand at several of the taps set into the marble pool, filling the tub with warm water.   
  
With everyone else in the school at dinner, this would be the perfect time to enjoy some sisterly bonding, and to teach Narcissa a lesson. The two had been sneaking into the prefects' bathroom ever since Bellatrix had conned the password out of a Slytherin prefect in her fourth year. The student bathrooms were simply too plebian for the Black sisters, and only this one, with its silver chandeliers and white marble furnishings, was opulent enough for them.  
  
"Everything off, Cissy, then get in the water," Bella said as she started unfasten her own robes. She watched as her little sister took off her knee socks, bra, and knickers. All of the items were white cotton, and Bella wondered idly if her sister had chosen them with the intent of appearing innocent. If so, it was a wasted attempt — Narcissa was too corrupted to wear virginal white.   
  
Or she would be, rather, when Bellatrix was done with her.   
  
Joining Narcissa in the water, Bella directed her to sit on one of the benches carved into the side of the pool. She knelt over Cissy's legs, looked down at her sister, and asked, "Do you trust me?"   
  
"Yes, Bella," Narcissa said instantly, staring at the breasts in her face. Her sister was being a horrid tease; Narcissa longed to lick one of the nipples right in front of her, as Bella often did to her, but she wasn't allowed to. Not yet, anyway.  
  
"Good girl," Bellatrix purred and tipped her head down, capturing her sister's mouth in a possessive kiss as she loosened her bladder, claiming and punishing Cissy all at once.   
  
Narcissa started struggling when she realized Bella was  _pissing on her_ , but she was trapped between her sister's lips and the marble wall of the pool. She closed her eyes, holding back tears, as the hot pee dribbled down her belly and between her thighs before washing away in the water.   
  
"Shh," Bellatrix whispered when she was done, and lightly kissed each of her sister's trembling eyelids. "You're my good girl, Cissy."   
  
" _Why?_ " Narcissa demanded, opening her eyes and glowering at Bellatrix.   
  
Reaching for a bottle of shampoo sitting on the edge of the tub, Bella poured some into her hand. Motioning for Cissy to turn, she began to wash her sister's hair to calm her, massaging the jasmine-scented liquid into the blonde strands. "You're mine," she said simply. "It wasn't that bad, was it?"   
  
Narcissa relaxed slowly under Bella's soothing hands, her shock and anger fading as she thought about what had happened. It hadn't been bad, exactly, but it had been humiliating, and she hated feeling that way. "No," she admitted reluctantly, "but I didn't like it."   
  
"Oh, Cissy, you aren't supposed to like it," Bella laughed, a rich sound that echoed off the walls. "It's supposed to teach you a lesson. You aren't going to borrow Andromeda's trousers again, are you?" Finishing with her sister's hair, she scooped up a handful of purple bubble foam and soaped Narcissa's back.  
  
"I suppose not," Narcissa tried to say seriously, but broke into giggles when Bella's hands reached her bum. Her laughs soon turned to sighs when her sister's fingers moved around to her belly and hips, gently rubbing the same areas she'd marked earlier. "Bella," she moaned, "when are we going to—"  
  
Bellatrix knew exactly what Cissy was asking for. She'd been teasing her sister for months, ever since Narcissa had turned sixteen, but hadn't followed through — yet. Playing with Cissy, dragging out the seduction until her sister  _longed_  for her, only increased Bella's own desire. Most nights she went to sleep with the thought of Cissy's head between her thighs; even now, she wanted nothing more than to feel her sister's mouth on her aching quim. Staking her claim over Cissy had aroused her more than she'd expected.  
  
"Soon, darling," Bellatrix whispered into Narcissa's ear, and then followed the words with her tongue, licking along the curve of her sister's ear before nibbling lightly on the lobe. Her teeth pulled at the diamond earring her sister wore before letting go, and Bella smiled knowingly when Cissy sighed wistfully at the loss of contact. After months of exploration, her teeth and tongue knew every single erogenous zone on her sister's body.  
  
Wondering if the 'punishment' had affected Narcissa as strongly as it had her, Bella pushed a hand roughly between Cissy's thighs, and a wicked idea popped into her head when she felt a wetness that had nothing to do with the water they were in.   
  
Narcissa yelped when she was suddenly lifted out of the water and set on the edge of the tub. "It's cold!" she shrieked when her bum touched the marble tile, and started to push off to slide back into the warm water, but a hand on her knee stopped her.   
  
"I'll warm you up," Bellatrix purred, and Narcissa's insides squirmed excitedly from the look on Bella's face. "Legs, Cissy," she said, and the blonde obediently spread her thighs, displaying her pussy for Bella to play with. As her sister crept a hand up her leg, Narcissa leaned back on her hands to brace herself, wondering if she was finally about to orgasm from Bella's touch.   
  
Bellatrix licked her lips as she slowly, ever so slowly, moved her left hand up Narcissa's slender thigh, the pads of her fingers ghosting lightly over her sister's sensitive skin. She heard a few more giggles as she walked her fingers up the pale skin; Cissy was incredibly ticklish on her upper thighs. The nervous laughs deepened to throaty moans when Bella's thumb reached Narcissa's clitoris, pressing and rolling the little nub, providing the sort of stimulation her sister loved.  
  
She kept up the gentle pressure and circling motions until Narcissa's hips started thrusting forward, asking for more. Those undulating, begging hips meant Cissy was on the brink of a climax, and Bella pulled her hand away; she didn't want her to come, not yet.   
  
Warmth pooled between Bella's thighs when she looked up and saw that Narcissa's cheeks were flushed and her head was flung back, her long hair dripping on the floor as she cried, " _Bellaaaa!_ "   
  
"Not yet, Cissy," Bella said, her eyes greedily drinking in Narcissa's wet, disheveled, uncontrolled appearance. Her lower lip curled in a smirk when her sister glared at her; Narcissa's haughty expression was much less effective when those light blue eyes were unfocused and desperate, and when those pale cheeks were bright pink with excitement.   
  
"Hmph."   
  
Bellatrix let her stew for a few minutes before reaching again for Narcissa. "It's a Hogsmeade day tomorrow," she said thoughtfully as her fingers toyed with the blonde curls at the apex of Cissy's thighs. When her thumb brushed against her sister's clitoris, Narcissa hissed sharply, and Bella felt a twinge between her legs. "Everyone will be there — except you."   
  


*     *     *

  
  
"Now  _this_  is how I like you," Bellatrix said happily when Narcissa slipped into her room the next morning. All the other seventh year girls had already departed for Hogsmeade, as had just about everyone else in the Slytherin dormitories, leaving the two sisters alone.  
  
Her sister was wearing her Hogwarts uniform, the picture of an innocent schoolgirl from head to toe. With her flawless pale skin, long gold hair, and bright blue eyes, Narcissa looked like one of the dolls Bella had received as a child for birthdays or Christmas. She'd never cared for those delicate china toys, had always found them too breakable and dull, but Narcissa …  _she_  was the absolute perfect doll for a girl like Bellatrix.   
  
"See? I said I would be good." Narcissa twirled and her pleated skirt swirled about her legs, revealing a hint of black lace high on her thighs.   
  
"Come here," Bella ordered, but her voice was much softer than yesterday. Today she was quite excited at the thought of what she was about to do; her insides were already twisting in anticipation. "Do you trust me?"   
  
This was the question that had turned Narcissa into willing prey for her predator-like sister, that had changed their childhood games into a cat and mouse pursuit. This was the question that sent sparks of arousal to Narcissa's belly, that melted her glacial exterior until she was a quivering mess.  
  
"Yes, Bella."   
  
"Take your jumper off, then lie down." Narcissa did so, and toed off her shoes for good measure, before jumping eagerly on her sister's bed. She watched as Bella moved to her wardrobe and pulled something out of a drawer. "Hand," her sister said when she came to the bed, and Narcissa obediently stretched her right hand out to Bella.   
  
Bellatrix kissed the inside of her sister's wrist before she used a green and silver Slytherin tie to bind it to the bedpost, then repeated the process on Narcissa's left arm. She watched as Cissy bit her lip and tugged at her bonds, pleased with how easily her sister had submitted.   
  
She had planned on taking her time with this first experience, dragging it out as she had dragged out the months of teasing, but the sight of Cissy, bound so prettily to her bed, changed Bella's mind. Abruptly, her hands reached for the white button-down shirt Cissy wore and she ripped it open so ferociously that buttons flew across the room.   
  
" _Bel—_ "   
  
Before Narcissa could say anymore, Bellatrix swallowed her protest with a rough kiss, thrusting her tongue deeply into her little sister's mouth. She sucked briefly on Cissy's lower lip before pulling back and trailing her mouth along her sister's throat, over the bump of her collarbone, moving her head down until her lips touched the lace of Narcissa's bra.   
  
As Bella tongued her sister's nipples, teasing and hardening them through the thin lace covering them, her hands rolled up Cissy's wool skirt. When her fingers felt lace-top stockings, and then garter straps, she smiled and whispered, "Such a good girl."   
  
Another reason why Bellatrix loved Narcissa was that she could dress her little sister up in a way that excited her. Knowing that Cissy went to classes and meals and everything else wearing what Bella wanted — silk stockings and lacy lingerie — drove her absolutely crazy. That was why she'd been so upset the day before to find Narcissa in trousers. Sometimes it was only the thought of her sweet sister dressed so naughtily beneath her uniform that made her days bearable. Because  _that_  led to thoughts of doing  _this_ , of teasing and licking and  _fucking_  Narcissa with her tongue.  
  
Bella slipped a hand up her skirt as she sat up and gazed at her sister. Narcissa looked so beautiful, with her pink lips kiss-swollen, her blue eyes half-hooded with arousal, her silk-clad legs spread wantonly, and her small hands straining against the ties.   
  
"You're — a — tease — Bella," Narcissa whined when she noticed her older sister was touching herself. She watched, pulling against her bonds, as Bella's dark blue eyes glazed with lust, as her breathing quickened and hitched in her throat, as her mouth fell open an 'O.' Unable to take it any longer she begged, "Please, Bella!  _Please!_ "  
  
Narcissa's pleas were like a musical aphrodisiac, and with a groan Bella pulled her hand away just before she came. She would orgasm when Cissy did, and not a moment before.  
  
Fumbling for her wand, Bellatrix vanished Cissy's lacy black knickers, but left the matching garter belt and silk stockings, liking how they nicely framed Narcissa's pussy. She gripped each slender thigh, spreading her sister's legs apart even more, then bent her head and swiped her tongue along the length of her sister's cunt. Cissy was so wet that Bella's tongue slid easily in and out of the slick folds as she slowly licked her way up to Narcissa's clitoris.   
  
At the first touch of Bella's tongue — _finally_  — Narcissa's hips bucked violently, and only the hands on her thighs kept her pelvis on the bed. When Bella purred huskily, "You taste  _so_  good, Cissy," the feel of her sister's breath on her throbbing folds made her shriek. She writhed frantically when Bella reached her clit and circled it with her tongue, and Narcissa's eyes rolled back in her head when Bella sucked it between her lips.   
  
When Cissy started begging incoherently, whimpering and gasping in the most delicious manner, Bella let go of one leg and pressed her hand to her own cunt. As Bellatrix flicked the tip of her tongue against Cissy's sensitive nub she humped her hand, mashing her clitoris against her palm, seeking the mix of pain and pleasure that she needed to get off.  
  
" _Bella!_ "   
  
Narcissa's thighs clamped down on Bella's head when she came, pressing her sister's face into her quim. Her orgasm triggered her sister's, and Bellatrix growled, " _Cisssssy,_ " as she climaxed, her voice muffled by Narcissa's cunt.   
  
By the time Bella was able to raise her head, Narcissa had slumped back on the bed, breathing heavily, her arms slack in their tie bondage. Lazily Bella undid the silk ties and gently lowered her sister's wrists, again kissing each one with a gentle press of her lips, soothing away the marks the ties had left. Then she lay down beside Narcissa and gathered her sister into her arms, holding her as they both recovered.  
  
Eventually, when both had quit panting and were instead lying comfortably, snuggled together, Bellatrix asked, "Are you always going to be my girl, Cissy?" She tenderly tucked a strand of tangled blonde hair behind her sister's ear, waiting for an answer.   
  
Narcissa looked up, and Bella's heart swelled when she saw the love in her baby sister's eyes. "Always, Bella," she murmured sleepily. 

**Author's Note:**

> This fic was originally written in November 2010.
> 
> Come visit me on [tumblr!](http://galacticcoyote.tumblr.com/)


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